The invention relates to an ultrasonic imaging apparatus operating according to the impulse-echo method, particularly intended for medical diagnostics, comprising an ultrasonic applicator for the linear ultrasonic scanning of an examination subject and an image display device with a line generator for the reproduction of the echo impulses as lines, as well as an image generator for the displacement of the line as a function of the displacement of the ultrasonic beam in the subject, whereby, proceeding from a prescribable line sweep time of a picture tube as the image display installation, for example, from the standard line sweep time of a television picture tube, the period time of the ultrasonic transmission/reception cycles of the ultrasonic applicator is adjusted to a value which corresponds to a whole multiple of the line sweep time of the picture tube and whereby echo signals arising at the rate of these transmission/reception cycles are stored for each cycle in alternating memories until the next successive one and are only read out to the picture tube during this next succesive cycle, whereby the reading out ensues singly or mutliply in such reading-out times which correspond to the line sweep time of the picture tube.
Such an imaging apparatus is known for example from the German Offenlegungsschrift No. 2,629,895. It specifically renders possible a video-standard conversion with only a maxiumum of two memories for the intermediate storage of the echo signals of two respective successive scanning lines. Thereby, the conversion of the ultrasonic image ensues in the direct process.
In practice, not only the direct presentation of the image directly scanned at the current point in time is of interest; the reproduction of stored images is also of significance. By this means, one obtains a stationary image which facilitates the mensuration of the ultrasonic image on the picture screen. The diagnostic statement is also facilitated by means of stationary images, for example, upon later reproduction.
For the presentation of digitally stored images, particularly in the television standard, up to now total image memories (so-called orthogonal memories) which have a very high technical outlay were required, with whose help, thus, only an already converted, complete image could be stored and again polled. An ultrasonic image apparatus with such a memory system is already known, for example, from the German Offenlegungsschrift No. 2,619,684.